The objective of the proposed research is to demonstrate that high specific activity, tritium labeled peptide and protein hormones can be prepared which are biologically active and are suitable for biochemical and physiologic studies of the metabolism, mechanism of action and production of these hormones. To this end, a series of peptide and protein hormones of increasingly complex structure will be labeled by the tritium-hydrogen exchange method developed in this laboratory which utilizes microwave discharge activation of tritium gas. It is expected that a detailed description of the chemical and biological consequences of tritium atom reactions with these molecules will provide model studies for validating the general applicability of this method which is uniquely suited for the preparation of tritium labeled tracers of peptide hormones. Utilizing these tracers in specific biochemical studies, we also hope to demonstrate its general utility for the study of previously inaccessible aspects of endocrine biochemistry.